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C h activation thesis proposal

C h activation thesis proposal sign for any concerted


Chen, George S. (2010) Mechanisms of C-H Bond Activation by Platinum(II). Dissertation (Ph.D.), California Institute of Technology. resolver.caltech.edu/CaltechTHESIS:12012009-210811032


The rates of C–H bond activation for many alkanes by [(N–N)Pt^II(CH_3)(TFE-d3)]^+ (N–N = Ar–N=C(CH_3)–C(CH3)=N–Ar Ar = 3,5-di-tert-butylphenyl TFE-d_3 = CF_3CD_2OD) were studied. Both straight line and cyclic alkanes give you the corresponding [(N–N)Pt^II(H)(alkene)]^+ cation. Second-order rate constants for cycloalkane activation (C_nH_(2n)) are proportional to what size the ring (k

n). For cyclohexane, the deuterium kinetic isotope effect (k_H/k_D) of merely one.28(5) is comparable to the suggested rate exercising alkane coordination to make a C–H complex. Evaluating the relative rates of cyclic and straight line alkanes signifies the platinum center is fairly unselective regarding different C–H bonds: the speed constants (per C–H bond) for the substrates examined all belong to a narrow range, there doesn’t seem to become any significant preference for either primary or secondary C–H bonds.

The protonolysis of platinum(II) methyl complexes was investigated by both experiment and computation. Experimental results proven that protonolysis of (COD)Pt^II(CH_3)_2 (COD = 1,5 – cyclooctadiene) by trifluoroacetic acidity gave abnormally large (more than 10) kinetic isotope effects (k_H/k_D) at 70 levels and greater. The top temperature dependence of k_H/k_D for the protonolysis of (COD)Pt^II(CH_3)_2 gave Arrhenius parameters outdoors semi-classical limits. However, protonolysis of (tmeda)Pt^II(CH_3)Cl (tmeda = N,N,N’,N’–tetramethyl–ethylenediamine) by trifluoroacetic acidity gave normal kinetic isotope effects and classical Arrhenius parameters.

C h activation thesis proposal improved as compared to the

Density functional theory (DFT) was applied to look into the mechanism of protonolysis in the systems, along with the effects were seen to become in line with experimental observations. According to our experimental and computational work, we advise that protonolysis of methylplatinium(II) complexes can happen most likely through a concerted or stepwise path that’s highly ligand dependent more electron-wealthy ligands will favor the stepwise mechanism, while electron-deficient ligands with elevated effective trans influence will favor the concerted mechanism. Finally, we advise that the existence of abnormally large KIEs can be a sign for almost any concerted path, which prone to association relating to the magnitude and temperature dependence within the KIE and mechanism.

In aqueous solution, [Pt^II(glycinato)Cl_2]^- catalyzes oxidation by [Pt^IVCl_6]^(2-) within the methyl volume of p-toluenesulfonate for that corresponding alcohol and aldehyde, without any further oxidation for that carboxylic acidity. Both rate and selectivity are improved compared to original Shilov system which utilizes [Pt^IICl_n(H_2O)_(4-n)]^(2-n) because the catalyst.

Thesis (Dissertation (Ph.D.))

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